add missing closing quote in code example

Author: olvidalo

data/newrangeindex.xml

@@ -246,7 +246,7 @@
                     <programlisting language="xml">&lt;range>
     &lt;create qname="tei:term">
         &lt;condition attribute="type" value="main"/>
-        &lt;field name="mainTerm" type="xs:string/>
+        &lt;field name="mainTerm" type="xs:string"/>
     &lt;/create>
 &lt;/range></programlisting>
                 </example></para>